Heinrich L., Muche L.: Second-order properties of the point process of nodes in a stationary Voronoi tessellation. Math. Nachr. 281, No. 3, 350 - 375. [DOI: 10.1002/mana2005106.07] [PDF 984 KB] see in addition [PDF 738] (The first version of this paper with a detailed proof of Lemma 3.1 appeared under the title "On the pair correlation function of the point process of nodes in a Voronoi tessellation" as Preprint No. 94-07 (1994), Fakultät für Mathematik und Informatik, TU Bergakademie Freiberg, 30 pages, [PDF 228 KB] ).